Gastroenterologists Publish Recommendations on IBS Treatment

by John Gever John Gever,Senior Editor, MedPage Today
December 18, 2008

Action Points

Explain to interested patients that the recommendations were based on a review of published studies of treatments for irritable bowel syndrome.

Explain that these are general recommendations and are not meant to apply to all patients. Patients' individual characteristics and symptoms may warrant therapies other than those recommended in published guidelines.

BETHESDA, Md., Dec. 18 -- Lubiprostone (Amitiza), psyllium husk, and rifaxamin (Xifaxan) were some of the treatments given a thumbs-up by the American College of Gastroenterology (ACG) for treating irritable bowel syndrome.

Updated recommendations for managing IBS were published in a supplement to the January issue of the American Journal of Gastroenterology. The authors, headed by Lawrence Brandt, M.D., of Montefiore Medical Center in New York, were members of a task force on IBS assembled by the college.

The recommendations were based on a review of more than 300 published studies on the natural history of IBS, its differential diagnosis, and dozens of therapies that have been tried.

Probiotics: Products based on Bifidobacteria have shown some benefit, but Lactobacillus-based mixtures have not.

5-HT3 receptor antagonists: Alosetron (Lotronex) relieves global IBS symptoms in men and women with diarrhea-predominant symptoms. But because of potentially serious side effects, it's available to women only through a special access program.

Lubiprostone: It is better than placebo at reducing symptoms of constipation-predominant IBS, especially in women.

Antidepressants: Selective serotonin receptor antagonists reduce pain and global symptoms of constipation-predominant IBS, and low-dose tricyclic agents also do so for diarrhea-predominant illness. But limited safety data exist on these agents.

Chinese herbal medicines: They have shown benefit in individual trials but the components vary and their safety is uncertain.

The ACG task force designated each recommendation as strong or weak, and also characterized the quality of supporting evidence as high, moderate, or low.

Most of the treatment recommendations were weak, because the underlying research suggested that the benefits only modestly outweighed the risks and burdens.

For example, the review found that for peppermint oil capsules, the number of patients who would have to be treated to prevent one patient from remaining symptomatic was 2.5, suggesting it's one of the most effective IBS treatments available.

But the finding was based on few, relatively low-quality studies. Moreover, raw peppermint oil can be intensely painful if it comes into contact with the upper digestive tract.

Hence, Dr. Brandt and colleagues graded the recommendation at 2C, the lowest level.

However, the use of non-absorbed antibiotics earned a strong recommendation for improving global IBS symptoms and bloating, as did the chloride channel activator lubiprostone for global symptoms in women.

In addition, antidepressants -- including tricyclics as well as serotonin reuptake inhibitors -- appear to be effective at reducing abdominal pain and global symptoms. All three recommendations were based on moderate-quality evidence.

Dr. Brandt and colleagues also gave several strong recommendations regarding diagnosis and non-pharmacologic treatments -- particularly strategies to avoid.

For example, the group said that extensive testing to rule out colon cancer and inflammatory bowel disease is unwarranted for most younger patients, unless they have "alarm features."

Those include fever, bleeding, unexplained weight loss, or a family history of serious intestinal diseases.

But testing for celiac disease may be worthwhile in patients with diarrheal IBS, the researchers said.

The panel also said there was little evidence to support exclusionary diets to treat IBS, except in patients with demonstrated problems with dairy products.

Some psychotherapies, including cognitive behavioral approaches, dynamic therapy, and hypnosis have also been shown to be effective, although the evidence remained weak, Dr. Brandt and colleagues said.

However, they found no good evidence whatsoever to support relaxation therapy for IBS.

The review also identified several emerging classes of medications that may be helpful in IBS. These include calcium channel blockers, serotonin and adrenergic receptor modulators, and opioid receptor ligands. But only a handful of these investigational agents have reached phase III trials, the researchers found.

No external funding for the systematic review was reported.

No potential conflicts of interest were reported.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco

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